Kelly, John K.Holeski, Liza M.Arathi, H. S.2015-02-032015-02-032008-01-01Kelly, John K.; Holeski, Liza M.; Arathi, H. S. (2008). "The genetic correlation between flower size and water use efficiency in monkeyflowers." Evolutionary Ecology Research, 10(1):147-152. http://www.evolutionary-ecology.com/issues/v10n01/llar2269.pdf1522-0613https://hdl.handle.net/1808/16500This is the publisher's version, also available electronically from http://www.evolutionary-ecology.com/.Question: Does water loss during drought stress represent an important physiological constraint on the evolution of flower size? Organism: A genetically diverse population of Mimulus guttatus (yellow monkeyflower) originally sampled from an alpine meadow in Oregon, USA. Methods: We grew plants of three different genotypic classes (small, medium, and large flowered) under both well-watered and drought-stress conditions and measured water use efficiency using stable carbon isotopes. Results: There was no difference in water use efficiency among flower size genotypes under well-watered conditions, but the water use efficiency of small-flowered plants was substantially lower than that of medium or large genotypes under drought stress. Whether this paradoxical result is a direct effect of flower size or an indirect (i.e. pleiotropic) effect, the presence of a genetic correlation between floral and physiological traits indicates that selection of one does impact the other.ArticleopenAccess